High performance stainless-steel supported Pd membranes with a finger-like and gap structure and its application in NH3 decomposition membrane reactor

Pd composite membranes show great potential in several important fields, such as H-2 production for fuel cell or pre-combustion applications. This study presents a facile and effective approach to develop high performance stainless-steel supported Pd composite membranes with a finger-like and gap structure by coating the finger-like porous stainless-steel support (PSS) with MnCO3 particles, which forms a small gap of ca. 1 mu m during subsequent thermal treatment. The stability of this novel configuration was demonstrated under 20-50 fast heating up/cooling down cycles at a maximum ramp rate of 10 K/min, under near practical fuel cell application conditions. Such a structure imitates semi-free-standing bulk Pd membranes, which not only avoids the direct contact between Pd layer and PSS and ensures a high H-2 permeance, but also avoids the shear stresses between the metal membrane and module. The membrane with a finger-like and gap structure was applied in NH3 decomposition membrane reactor, which achieved nearly complete NH3 conversion at a relatively low temperature of 673 K and remained stable for 200 h, exhibiting potential in future applications.